用户指南和参考

ST_PolyFromWKB

ST_PolyFromWKB 接受多边形类型的公认二进制表示和 Spatial 参考系标识,以返回多边形。

语法

db2gse.ST_PolyFromWKB(WKBPolygon Blob(1M), SRID Integer)

返回类型

db2gse.ST_Polygon

示例

以下代码段填充 SENSITIVE_AREAS 表。

除了包含 zone 列(用于存储公共设施的多边形几何图形)之外,SENSITIVE_AREAS 表还包含描述受威胁的公共设施的几列。

CREATE TABLE SENSITIVE_AREAS (id        integer,
                              name      varchar(128),
                              size      float,
                              type      varchar(10),
                              zone      db2gse.ST_Polygon);
 
 
/* Create the SQL insert statement to populate the id, name, size, type and
   zone. The question marks are parameter markers that indicate the id,name,
   size, type and zone values that will be retrieved at runtime. */
strcpy (shp_wkb,"insert into SENSITIVE_AREAS (id, name, size, type, zone)
values (?,?,?,?, db2gse.ST_PolyFromWKB (cast(? as blob(1m)),
db2gse.coordref()..srid(0)))");
 
/* Allocate memory for the SQL statement handle and associate the
   statement handle with the connection handle. */
rc = SQLAllocStmt (handle, &hstmt);
 
/* Prepare the SQL statement for execution. */
rc = SQLPrepare (hstmt, (unsigned char *)wkb_sql, SQL_NTS);
 
/* Bind the id integer value to the first parameter. */
pcbvalue1 = 0;
rc = SQLBindParameter (hstmt, 1, SQL_PARAM_INPUT, SQL_C_INTEGER,
   SQL_INTEGER, 0, 0, &id, 0, &pcbvalue1);
 
/* Bind the name varchar value to the second parameter. */
pcbvalue2 = name_len;
rc = SQLBindParameter (hstmt, 2, SQL_PARAM_INPUT, SQL_C_CHAR,
   SQL_CHAR, 0, 0, name, 0, &pcbvalue2);
 
/* Bind the size float to the third parameter. */
pcbvalue3 = 0;
rc = SQLBindParameter (hstmt, 3, SQL_PARAM_INPUT, SQL_C_FLOAT,
     SQL_REAL, 0, 0, &size, 0, &pcbvalue3);
 
/* Bind the type varchar to the fourth parameter. */
pcbvalue4 = type_len;
rc = SQLBindParameter (hstmt, 3, SQL_PARAM_INPUT, SQL_C_CHAR,
     SQL_VARCHAR, type_len, 0, type, type_len, &pcbvalue4);
 
/* Bind the zone polygon to the fifth parameter. */
pcbvalue5 = zone_len;
rc = SQLBindParameter (hstmt, 3, SQL_PARAM_INPUT, SQL_C_BINARY,
     SQL_BLOB, zone_len, 0, zone_wkb, zone_len, &pcbvalue5);
 
/* Execute the insert statement. */
rc = SQLExecute (hstmt); 


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